1. Field of the Invention
The present invention relates to a solid-state imaging device comprising a through-electrode formed on a semiconductor substrate, for example, a camera module.
2. Description of the Related Art
With the miniaturization of electronic equipment, semiconductor devices to be mounted in such equipment need to be miniaturized and integrated at high density. In the late 1990's, research into the practical application of a wafer-level chip-scale package (CSP) began (for example, see Nikkei Microdevices, April, 1998, pp. 28, 164, and 176). This is a flip-chip method using no lead wire, the method including connecting a substrate and a semiconductor chip by a bump such that the surface of the semiconductor chip faces downward.
In contrast, the development of a stacked package (multi-chip package) in which a plurality of semiconductor chips are three-dimensionally stacked to realize considerable miniaturization has been in progress since the late 1990's. A package using a through-electrode has been proposed (for example, see Jpn. Pat. Appln. KOKAI Publication No. 10-223833). Research into a wafer level CSP for an optical element began in about 2000.
In International Electron Devices Meeting 1999 Technical Digest pp. 879 to 882, a structure of glass+adhesive layer+image sensor+through-electrode by Koyanagi et al. and an actually created sectional photograph are described. Similarly, also in the specification of U.S. Pat. No. 6,489,675 and Jpn. Pat. Appln. KOKAI Publication No. 2007-53149, a sectional structure of an optical element comprising a through-electrode and an optically transparent support substrate is disclosed.
However, since the through-electrode proposed by all the documents is formed in a silicon semiconductor substrate, because of a coupling between a through-electrode and a silicon semiconductor substrate, a high ground resistance near the through-electrode, or the like, power supplied from a pad through the through-electrode is degraded. In contrast to this, because of power supply noise generated by a silicon semiconductor substrate side, a desired preferable voltage waveform cannot be achieved.